What causes rheumatoid arthritis?

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The exact causes of rheumatoid arthritis are not entirely known, but scientists believe that a combination of environmental and genetic factors may make people more susceptible to developing this condition. Â For example, researchers believe that either a viral or bacterial infection can trigger this disease if a person is genetically predisposed to it.

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Scientists define rheumatoid arthritis, or RA, as an autoimmune disorder in which the immune system attacks the synovium, resulting in its inflammation. The inflammation causes damage to the cartilage and bone of the joint. The synovium is the lining around the joints.

Some other symptoms of RA include joint stiffness, warmth around the affected area and fatigue. Factors that may increase a person's risk for RA are sex, age and genetics. Rheumatoid arthritis is more prevalent among women than men. People, who have a family member with this condition, may have an increased risk factor for RA. Although anyone can get RA at any age, its onset usually manifests between the ages of 30 and 50.